The term 'alternative investment' can be used for anything outside the staple financial assets of shares, bonds and cash, but in its truest sense it refers to an investment that has a low correlation with these markets, and therefore offers diversification. Non-financial alternatives span a broadrange including precious metals, diamonds, antiques, coins and various other collectables among other things.
Alternatives have a number of pros and cons. On the plus side, apart from providing diversification, they may offer a great deal of enjoyment, whether through researching the subject, ownership, or even - in the case of wine - consumption along the way.
On the negative side, alternatives are not generally regulated; successful investment depends upon expert knowledge - which you may have to pay for; and investments are likely to be relatively illiquid, so they may be a lot easier to buy than to sell. And just like conventional financial investments, their value can of course go down as well as up.
Click on the website of London's White Cube gallery (whitecube.com), pick 'shop' from the menu, and within a few seconds a piece of art by Damien Hirst could be yours.
Just under £3,000 would secure you one of his spot compositions; for £3,500 you could buy a butterfly called Hope; or for £950 an image of a diamond-encrusted skull entitled For the Love of God Believe.
All are limited-edition prints, of course, but this instant access to the work of arguably the world's most famous living artist illustrates how the process of buying art has been transformed in the past few years.
What was once a closed, esoteric world of intimidating galleries and exclusive private views is now open to all.
Charles Saatchi became one of the most influential art collectors in the world through quietly buying up the works of Hirst and other so-called Young British Artists when they were unknown; today Saatchi Art is a California-based website with thousands of pictures and other artworks from all over the world, where you can work with your own art curator to choose acquisitions and receive personalised recommendations.
More on alternative investments
This is just one of the dozens of online galleries and buying platforms now available - even Amazon has launched its own art marketplace. Research by Hiscox estimated that the online art market was worth $1.57 billion (£970 million) in 2013 and growing fast.
And for those who want to buy in person, a year-round programme of art fairs now brings hundreds of galleries together under the same roof, providing buyers with limitless opportunity to find that obscure object of desire.
Investing profitably in art is a different matter, of course. While instances of artworks by the likes of Monet or Lucien Freud selling for millions grab the headlines, there is no single reliable measure of how art performs as an asset class.
get your eye in
There are a number of art market indices - such as Mei Moses World All Art Index - but these tend to track only a small number of high-value works sold in international auction houses. The aforementioned index shows average annual returns of 5.92 per cent over 15 years - outpacing the S&P 500 over the period.
Nicky Wheeler, managing director of the Affordable Art Fair, which holds 18 events each year around the world, advises you to begin by 'getting your eye in' and finding out what types of art you are drawn to.
If investment is your main priority, one option is to go for bankable names - whether contemporary, such as Hirst, Marc Quinn or Tracey Emin, or more traditional, such as Royal Academician Ken Howard.
A different strategy is to go for today's young, relatively unknown artists. 'We have a Young Graduates' exhibition which features work that we have picked from around the country,' says Wheeler. She gives an example: a work by Andrew Salgado featured in the 2009 show at £2,750. Comparable works by the artist are now selling for around £12,000.
You could choose to focus on a particular group of artists, or even a medium such as sculpture or photography. Pre-recession, says Wheeler, there was far more of a tendency for people to buy art for show; since then, she says, art buying is much more about 'considered consumption'.
She explains: 'People are buying something they really want to buy; after all, they are going to have it on their wall for a long time. There is also a return to a more skills-based rather than conceptual, in-your-face kind of approach.'
But unless you have really big money to spend, investing in art will always be a risky affair: the unknown artist you buy today may be even more unknown in 20 years, and some doubt that even the likes of Damien Hirst will stay the course. Buy for enjoyment first, and investment second, and your money will be well spent.
Collective routes to wealth and happiness
The Fine Art Fund Group (the fineartfund.com) has a number of art funds invested, including funds specialising in Middle East and Chinese art, typically with minimum investment of $500,000 and a 2 per cent management fee.
They have bought more than $150 million worth of artworks since starting in 2004. Investors in these funds have the option to borrow works and hang them in their own offices. However, there are no funds currently open.
The Modern Art Fund, set up by Castlestone Management, went into administration in 2011. Other funds tend to be offered privately.